Orientation measuring instrument

ABSTRACT

It is possible to generate a resonance mode such that a dielectric resonator (20) can be resonated and an electric field vector leaking out from the resonator (20) exists by arranging antennas (22a and 22b) for the resonator (20). When a sample (22) has dielectric anisotropy, the resonance frequency of the resonator (20) varies when the sample (25) or resonator (20) is rotated. The dielectric anisotropy of the sample (25) is found from the variance of the resonance frequency. Thus the dielectric anisotropy of not only a sheet-like sample, but also such a sample as a three-dimensional molded sample can be measured.

TECHNICAL FIELD

The present invention relates to an instrument measuring the orientationof those inclusive of sheet-like substances such as a polymer sheetincluding a film and paper and stereoscopic articles such as moldings ofplastic, resin, rubber and the like with a microwave.

BACKGROUND TECHNIQUE

The fiber orientation of paper corresponds to the chain direction ofmolecules forming fiber, and is closely related with curling, torsion,inclination of NIP (Non-Impact Printer) paper and the like. Standards infiber orientation are becoming strict particularly in these severalyears, and several types of measuring methods have been employed. Thereare a water diffusion method, a dynamic rupture intensity method, anultrasonic method, a microwave method and the like as such measuringmethods, and the correspondence between operations on a wire part andthe orientation is substantially being elucidated at present.

On the other hand, in the case of a polymer film, that forming the filmis not fiber, and anisotropy of the arrangement of molecular chains canbe grasped as the anisotropy of various physical properties, forexample, optical, electrical and mechanical intensity and the like.Therefore, inclusive of paper, polymer film and the like, theorientation can be collectively grasped as the anisotropy (molecularorientation) of the arrangement of molecular chains.

It is general that a solid polymer has orientation in the process wheremolecular chains are solidified from a fluidized state due to the shapethereof. Due to the orientation, anisotropy appears in a dynamic,thermal, optical or electromagnetic physical property. Consequently, forexample, anisotropy of the modulus of elasticity, anisotropy of theratio of heat contraction or the like, takes place to cause variousproblems in quality.

As methods of measuring such anisotropy, an X-ray diffraction method, aninfrared polarization method, a fluorescence polarization method, abirefringence method, an ultrasonic method, a microwave method and thelike are employed.

Among these methods, the X-ray diffraction method and the fluorescencepolarization method require time and labor for measurement, whilemeasurement is difficult in relation to a thick sample in the infraredpolarization method. The birefringence method is a method of opticallymeasuring anisotropy by utilizing a refraction phenomenon based onanisotropy of a refraction index, and an opaque sample cannot bemeasured since transparency with respect to visible light or nearinfrared light is required for measurement. The ultrasonic method is ofa contact type and hence unsuitable for a moving sample.

A method employing resonance of a microwave utilizes anisotropy of adielectric constant The dielectric constant has a constant relation alsowith a refractive index. The method employing a microwave is utilizedfor molecular orientation measurement regardless of presence/absence ofoptical transparency inclusive of paper and a polymer film.

FIG. 1 illustrates the principle of a conventional orientation meteremploying a microwave cavity resonator. It comprises a microwaveintroduction part 2 on one end portion and a microwave detection part 4on another end portion. The part between these end portions defines amicrowave resonator 6 formed by a waveguide having a constant electricfield vibrational direction. The resonator 6 is provided with a slit 8in a direction perpendicularly crossing the axis of the resonator 6 onthe position of a loop part of a standing wave. A sample 10 is arrangedin the slit 8, a microwave is introduced from the microwave introductionpart 2, and the microwave intensity is detected with the microwavedetection part 4. The sample 10 is rotated around the axis of theresonator 6, and the intensity of the transmitted microwave is detectedevery rotational angle for obtaining the orientation pattern. It is alsopossible to obtain a dielectric constant pattern by obtaining thedielectric constant every rotational angle position from deviationbetween the resonance frequency when arranging the sample 10 in the slit10 and the resonance frequency when arranging no sample.

As a method of measuring the dielectric constant with a microwave, thatshown in FIG. 2 is proposed (refer to Japanese Utility Model Laying-OpenGazette Jitsu Kai Hei 3-70368). There, it comprises a pair of dielectricresonators 12 a and 12 b opposite to each other through a sample 10. Apair of terminals 14 a and 14 b oppositely arranged through thedielectric resonator 12 a are provided on side portions of onedielectric resonator 12 a. An electric field vector having one directionparallel to the plane of the sample 10 is generated in the dielectricresonators 12 a and 12 b by these terminals 14 a and 14 b, for measuringthe dielectric constant from the resonance characteristics thereof.Here, the terminals 14 a and 14 b are loop-like. It is also possible tocomprise a plurality of pairs of terminals 14 a and 14 b and measuredielectric anisotropy of the sample by switching operations thereof.

In the measuring instrument shown in FIG. 1 or FIG. 2, cavity resonatorsor dielectric resonators are oppositely arranged on both sides throughthe sample 10, and hence the shape of the measured sample 10 is limitedto a sheet-like one.

Accordingly, a first object of the present invention is to make itpossible to measure dielectric anisotropy not only in a sheet-likesample but also in a sample such as a stereoscopic molding.

An electric field vector in an in-sample plane required is desirablymore uniform during measuring the dielectric anisotropy.

While the terminals 14 a and 14 b are loop-like in the measuringinstrument shown in FIG. 2, a second object of the present invention isto find a terminal shape which can further attain uniformity of anelectric field vector than the loop-like terminal and improvesensitivity of dielectric anisotropy measurement.

DISCLOSURE OF THE INVENTION

One aspect of the present invention comprises a dielectric resonatorhaving a plane being close to or being in contact with a sample, amicrowave exciter generating an electric field vector having aunidirectional component at a frequency in the vicinity of the resonancefrequency of the dielectric resonator when the sample is present and inan in-sample plane parallel to the said plane in the dielectricresonator, a detector detecting transmission energy or reflection energyby the dielectric resonator, a rotation mechanism rotating the sample orthe dielectric resonator in a plane parallel to the said plane, and adata processor obtaining dielectric anisotropy of the sample fromvariance of a detection output of the detector following rotation by therotation mechanism.

This aspect is suitable for obtaining the dielectric anisotropy of aspecific part of the sample.

Another aspect of the present invention comprises a plurality ofdielectric resonators comprising planes being close to or being incontact with a sample and arranged close to each other, a microwaveexciter generating electric field vectors having unidirectionalcomponents, which are electric field vectors having directions differentfrom each other at a frequency in the vicinity of the resonancefrequency of the dielectric resonators when the sample is present and inan in-sample plane parallel to the said planes in the respectivedielectric resonators, detectors for the respective dielectricresonators detecting transmission energy or reflection energy by thesedielectric resonators, and a data processor obtaining dielectricanisotropy of the sample from variance of detection outputs by thedetectors at the electric field vectors of different directions from theplurality of dielectric resonators.

According to this aspect, neither the sample nor the dielectricresonators may be rotated but the dielectric anisotropy of the samplecan be obtained by outputs from the plurality of dielectric resonators,whereby it is suitable for continuously measuring a sample flowingonline.

Still another aspect of the present invention comprises a dielectricresonator having a plane being close to or being in contact with asample, a plurality of sets, which are sets of microwave excitersgenerating electric field vectors having unidirectional components at afrequency in the vicinity of the resonance frequency of the dielectricresonator when the sample is present and in an in-sample plane parallelto the said plane in the dielectric resonator and detectors detectingtransmission energy or reflection energy by the dielectric resonator,arranged on positions different from each other with respect to thedielectric resonator, a switching driver selecting one set among theplurality of sets of microwave exciters and detectors and sequentiallydriving the same, and a data processor obtaining dielectric anisotropyof the sample from variance of detection outputs of the detectorsfollowing switching by the switching driver.

According to this aspect, neither the sample nor the dielectricresonator may be rotated but the dielectric anisotropy of the sample canbe obtained by switching operations of the sets of the microwaveexciters and the detectors by the switching driver, whereby it issuitable for continuously measuring a sample flowing online also in thiscase.

Variance of the detection output by the detector can be measured asvariance of the resonance frequency. The variance of the resonancefrequency can be measured as the shift quantity of the frequency itself.The variance of the detection output by the detector can also bedetected as variance of detection energy at a specific frequency.

Terminals of the microwave exciter and the detector can be renderedloop-like, or can be rendered rod-like terminals. When loop-like,coupling occurs through magnetic field, and when rod-like, couplingoccurs through electric field. Electric field distribution on theposition of the sample is decided by a resonance mode determined by theshape, the magnitude, an excitation method, the dielectric constant etc.of the dielectric resonator, and hence it is desirable to select such aresonance mode that an electric field as parallel as possible to theplane being close to or being in contact with the sample is produced.

The loop-like or rod-like terminals may be so arranged that thedirections of magnetic field distribution or electric field distributionin the resonance mode to be resonated and the magnetic field or theelectric field produced by the loop-like or rod-like terminalsvectorially coincide with each other, and are preferably arranged in thevicinity of or inside the dielectric resonator. For example, rod-liketerminals can be arranged in a direction perpendicular or parallel tothe plane of the dielectric resonator being close to or being in contactwith the sample.

When detecting transmission energy with the detector, the exciter andthe detector are connected respectively to a pair of loop-like orrod-like terminals oppositely arranged through the dielectric resonator.

Furthermore, when detecting reflection energy with the detector, theexciter and the detector are connected to one common loop-like orrod-like terminal arranged close to the dielectric resonator.

The dielectric resonator is a cylindrical resonator or a squareresonator.

The periphery of the dielectric resonator is preferably covered with ashielding material consisting of a conductive material except a samplemeasuring surface. Thus, the Q value of a resonance curve can beincreased. At this time, it is preferable that a shielding materialconsisting of a conductive material is arranged also above a samplemeasuring surface of the dielectric resonator so that the sample isarranged between the sample measuring surface of the dielectricresonator and the shielding material above the sample measuring surface.

FIG. 3(A) schematically shows one embodiment With respect to adielectric resonator 20, proper microwave loop antennas (or rodantennas) 22 a and 22 b are arranged on proper positions in properdirections with respect to the dielectric resonator 20. It is possibleto produce a resonance mode resonating the dielectric resonator 20,where an electric field vector leaking outward from the resonator 20 ispresent, by the antennas 22 a and 22 b. For resonance modes, there is aTM mode or a TE mode when the dielectric resonator 20 is square, andthere is an HEM mode or the like when it is cylindrical. The intensityof an electric field vector 24 substantially exponentially decreases asseparating from the dielectric resonator 20, while the resonancefrequency shifts by electromagnetic coupling in response to thedielectric constant of a sample by placing the sample 25 in separationfrom the dielectric resonator 20 by a small distance or in contact withthe dielectric resonator 20.

FIG. 3(A) schematically shows the structure in the case of employing acylindrical dielectric resonator as the dielectric resonator 20 andmaking an HEM_(11δ) mode, while a microwave going out from an oscillator26 generates an electric field through the loop antenna 22 a, and thedielectric resonator 20 resonates by electromagnetic coupling. Theresonance frequency in this case is decided by the dimensions and thedielectric constant of the dielectric resonator 20. Assuming that theradius of the cylinder of the dielectric resonator 20 is a, the lengthis L and the dielectric constant is ∈, the resonance frequency f (GHz)is approximately obtained as:

f=34(a/L+3.45)/a/∈^(½)

FIG. 3(B) expresses FIG. 3(A) as an equivalent circuit. With respect tothe resonance frequency when placing no sample, the resonance frequencyshifts by the capacitance Cr changing in response to the dielectricconstant of the sample 25 when placing the sample 25. When thedielectric constant of the sample 25 has anisotropy, the resonancefrequency also shifts with depending on the directions of the sample 25and the electric field vector 24.

FIG. 4 shows electric field distribution in the HEM_(11δ) mode. (A)shows electric field distribution on a horizontal plane around an end ofthe dielectric resonator 20, and (B) shows electric field distributionon a meridian section plane of φ=0 (φ: angle from a reference directionin the horizontal plane).

Returning to FIG. 3 and making description, the microwave going out fromthe oscillator 26 is magnetically coupled with the dielectric resonator20 by the loop antenna 22 a, and the dielectric resonator 20 can enter aresonant state. The electric field vector of the dielectric resonator 20appears in the form substantially parallel to the plane of the sample25, and interaction with a dipole moment provided in the sample 25 takesplace. Here, with rotating the sample 25 or the dielectric resonator 20in parallel planes of the sample 25 and the dielectric resonator 20 bydetecting microwave intensity appearing in a detector 28 incorrespondence to its rotational angle, the orientation state can beobtained from angle dependency of the intensity. A controller 30controls the frequency of the microwave generated from the oscillator 26and captures the microwave intensity by the detector 28. 32 is acomputer as a data processor obtaining the orientation state from theangle dependency of the detected microwave intensity.

The principle of orientation measurement is further described. In thedielectric resonator 20, there is relation shown in FIG. 5(A) betweenthe intensity of the transmitted microwave and the frequency. Thisresonance curve is referred to as a Q curve. With the sample 25 beingplaced, the Q curve varies by the following relation:$\frac{\omega - \omega_{a}}{\omega_{a}} \cong {\frac{1}{4\overset{\_}{W}}{\int_{\Delta \quad V}{\lbrack {{( {P + \frac{J}{{j\omega}_{a}}} ) \cdot E_{a}^{*}} + {\mu_{0}{M \cdot H_{a}^{*}}}} \rbrack {v}}}}$$\overset{\_}{W} = {\frac{1}{2}{\int_{V}{ɛ_{0}{E_{a}}^{2}{v}}}}$ω = 2π  f ω:  complex  angular  frequency  (sample)ω_(a):  complex  angular  frequency  (blank)P:  electric  polarization J:  conductive  current  densityE_(a):  electric  field M:  magnetic  fieldH_(a):  magnetization * :  indicates  that  it  is  a  complex  number

That showing the variance is FIG. 5(B). When the sample 25 hasanisotropy in a plane opposite to the dielectric resonator 20 and if thesample 25 or the dielectric resonator 20 is rotated in a plane parallelto the plane, the peak frequency (resonance frequency) of the Q curvevaries every relative rotational angle position (S) of the sample 25with respect to the dielectric resonator 20 as shown in FIG. 6(A), forexample. In this rotation, in a Q curve shifting to the highestfrequency side, for example, it is assumed that detected intensity ofthe transmitted microwave at the frequency is l and such a frequencythat detected intensity on the high frequency side is l/2 is f₁. Thedetected intensity of the transmitted microwave at each rotational angleat the frequency f₁ is shown as a section of FIG. 6(B). Rewriting itwith the rotational angle S on the horizontal axis, it becomes as shownin FIG. 7(A). Further rewriting it in a spherical coordinate system, itbecomes elliptic as shown in FIG. 7(B), and the orientation angle (φ)and the degree of orientation (a/b) can be obtained from this result. ais the major axis length of the elliptic, and b is the minor axislength.

The present invention comprises a dielectric resonator having a planebeing close to or being in contact with a sample, and rotates the sampleor the dielectric resonator in the plane or changes the direction of anelectric field vector while generating the electric field vector havinga unidirectional component at a frequency in the vicinity of theresonance frequency of the dielectric resonator when the sample ispresent and in an in-sample plane parallel to the plane. Alternatively,it comprises a plurality of dielectric resonators having planes beingclose to or being in contact with a sample and arranged close to eachother, and generates electric field vectors having unidirectionalcomponents which are electric field vectors having directions differentfrom each other at a frequency in the vicinity of the resonancefrequency of the dielectric resonators when the sample is present and inin-sample planes parallel to the planes in the respective dielectricresonators. Then, it obtains dielectric anisotropy of the sample fromvariance of a detection value of resonance energy following rotation ofthe sample or the dielectric resonators or change of the electric fieldvectors or detection values of resonance energy from the plurality ofdielectric resonators having different directions of electric fieldvectors. Thus, it is possible to measure dielectric anisotropy not onlyin the case where the shape of the sample is a sheet-like one but alsoin a sample such as a stereoscopic molding.

A moving sample can be continuously measured by rotating the dielectricresonator, changing the direction of the electric field vector orarranging a plurality of dielectric resonators having differentdirections of electric field vectors, so that it is applicable to onlinemeasurement on the production site.

Also, when the dielectric resonator is covered with a conductiveshielding member except a part where the sample is arranged, Q of aresonance spectrum increases and measurement with a considerate S/Nratio is enabled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view showing a conventionalorientation measuring instrument employing a microwave cavity resonator.

FIG. 2 is a sectional view showing a conventional orientation measuringinstrument employing a dielectric resonator.

FIG. 3(A) is a schematic perspective view of one embodiment illustratingthe principle of the present invention, and

FIG. 3(B) is an equivalent circuit diagram thereof.

FIG. 4 shows electric field distribution in an HEM_(11δ) mode in adielectric resonator, (A) is electric field distribution on a horizontalplane in the vicinity of an end of the dielectric resonator, and (B) iselectric field distribution on a meridian section plane of φ=0.

FIG. 5(A) is a diagram of a Q curve showing the relation between theintensity of a transmitted microwave and the frequency in the dielectricresonator, and

FIG. 5(B) is a diagram showing resonance frequency shift followingdielectric constant change.

FIG. 6(A) is a diagram showing variance of a Q curve when rotating asample or a dielectric resonator, and

FIG. 6(B) is a diagram showing a section at a specific frequency.

FIG. 7(A) is a diagram rewriting the section of FIG. 6(B) with arotational angle S on the horizontal axis, and

FIG. 7(B) is a diagram further rewriting it in a spherical coordinatesystem.

FIG. 8 is a perspective view showing a first embodiment.

FIG. 9(A) is a diagram showing a transmission energy spectrum whenplacing no sample in a measurer of the embodiment, and

FIG. 9(B) is a diagram enlarging a part shown by arrow in (A).

FIG. 10 is a diagram showing a resonance peak around 5070.2 MHz in theembodiment, (A) is at blank measurement placing no sample, and (B) isthe case of placing paper as the sample.

FIG. 11(A) is a perspective view showing an embodiment measuringreflection energy by a dielectric resonator, and

FIG. 11(B) is a front elevational view showing a dielectric resonatorand a rod antenna there.

FIG. 12(A) is a diagram showing a reflection energy spectrum in blankmeasurement in the embodiment of FIG. 11, and

FIG. 12(B) is a diagram showing a peak thereof shown by arrow.

FIG. 13 illustrates diagrams showing peaks around 4575.875 MHz in theembodiment of FIG. 11, (A) is in blank measurement, and (B) is a case ofplacing paper as the sample.

FIG. 14 is a front sectional view showing an embodiment rotating adielectric resonator.

FIG. 15 is a schematic perspective view showing an embodiment having aplurality of dielectric resonators so set that directions of generatedelectric field vectors are different.

FIG. 16(A) is a schematic perspective view showing an embodimentcombining a square resonator and a rod antenna, and

FIG. 16(B) is a chart showing resonance modes and resonance frequenciesin the embodiment

FIG. 17(A) is a schematic perspective view showing an embodimentcombining a square resonator and a loop antenna, and

FIG. 17(B) is a schematic perspective view showing an embodimentcombining a square resonator and a rod antenna.

FIGS. 18(A) to (D) are diagrams showing electric field distribution inthe case of employing a loop antenna or a rod antenna in a cavityresonator and a dielectric resonator respectively.

FIG. 19(A) is a schematic perspective view showing a measuringinstrument combining a square resonator with a loop antenna,

FIGS. 19(B) and (C) are plan views showing states of making measurementby rendering directions of the sample different by 90 degrees, and

FIG. 19(D) is a diagram showing variation of a resonance spectrum withthe direction of the sample.

FIG. 20(A) is a schematic perspective view showing a measuringinstrument combining a square resonator with a rod antenna, and

FIG. 20(B) is a diagram showing variance of a resonance spectrumdepending on the direction of a sample.

FIG. 21(A) is a schematic perspective view showing an embodimentcomprising a shielding member, and

FIG. 21 (B) is a schematic perspective view showing an electric fieldvector of a dielectric resonator of this embodiment.

FIG. 22 is a diagram showing a resonance spectrum measuring a PET samplewith the embodiment of FIG. 21.

FIG. 23 is a diagram showing variance of a resonance frequency whenrotating a sample in a plane in the embodiment of FIG. 21.

FIG. 24 is a schematic block diagram showing another embodimentmeasuring dielectric resonance of a sample while rotating neither adielectric resonator nor the sample.

FIG. 25 is a block diagram schematically showing a computer as a dataprocessor.

BEST MODES FOR CARRYING OUT THE INVENTION

FIG. 8 shows a first embodiment A discharge polyethylene molding is putas a supporter 38 of a low dielectric constant in a cylindrical shieldcase 35 of brass whose upper part has an opening, and a cylindricaldielectric resonator 20 is mounted on the supporter 38 with the bottomsurface in the horizontal direction. In the dielectric resonator 20, itsupper surface is set substantially flush with an edge of the opening ofthe shield case 35, and a sample is placed on the opening part of theshield case 35. Orientation of the dielectric constant of the sample canbe measured by rotating the sample in a horizontal plane in the openingpart or rotating the dielectric resonator 20 in a horizontal plane.

Holding the dielectric resonator 20, a pair of loop antennas 22 a and 22b are arranged on both sides thereof, and loops thereof are fixed in aperpendicular direction. The loop antennas 22 a and 22 b are connectedwith respective connectors 34 a and 34 b through semi-rigid cables 36 aand 36 b, and connected to an oscillator and a detector from theconnectors 34 a and 34 b respectively.

FIG. 9 shows an example measuring resonance with this measuringinstrument while placing no sample. The horizontal axis shows amicrowave frequency, and the vertical axis shows transmission energy.(A) shows a transmission energy spectrum when scanning microwavefrequencies from 1000 MHz to 6000 MHz, while (B) is an enlargement ofthe area shown by arrow in (A), expressing a resonating state.

FIG. 10(A) shows a resonance peak at a microwave frequency of 5070.2 MHzwhen placing no sample (in blank measurement) in the embodiment. On theother hand, FIG. 10(B) shows resonance in the case of placing a sheet ofpaper on the opening part of the shield case 35 as the sample. It isunderstood that the peak position shifts to the lower frequency side byplacing the sample. When fixing the transmission frequency on theposition shown by arrow and making measurement, an output lowers byplacing the sample. By rotating the sample or the dielectric resonator20 in a plane parallel to the plane of the dielectric resonator 20,orientation can be measured as shown from FIG. 5 to FIG. 7 when thesample has anisotropy.

FIG. 11(A) shows an embodiment for measuring reflection energy by adielectric resonator 20, and a rod antenna 40 is arranged on the lowersurface side of the dielectric resonator 20 as shown in (B). The rodantenna 40 supplies a microwave from an oscillator to the dielectricresonator 20, while detecting the reflection energy by the dielectricresonator 20.

FIG. 12 shows a measurement result of the reflection energy in theembodiment of FIG. 11, and is an example of blank measurement in thecase of placing no sample. (A) shows a reflection energy spectrum whenscanning microwave frequencies from 1000 MHz to 6000 MHz, and (B) is anenlargement of the area shown by arrow in (A), expressing a resonatingstate. Absorption of energy occurs on the position of a resonancefrequency in the case of the reflection spectrum, and an absorption peakshown at (B) is obtained.

FIG. 13(A) shows a peak having the minimal point at 4575.875 MHz inblank measurement in the embodiment of FIG. 11. On the other hand, whenplacing a sheet of paper on the opening part of the shield case 35 asthe sample, the minimal position of the peak shifts toward a lowerfrequency side as shown in (B). Supposing that measurement is performedat the frequency of 4575.875 MHz, it is understood that the outputlowers by placing the sample. Also in this case, orientation can bemeasured as shown from FIG. 5 to FIG. 7 by rotating the sample or thedielectric resonator 20 in the plane parallel to the plane of thedielectric resonator 20, if the sample has anisotropy of the dielectricconstant.

FIG. 14 shows a concrete example rotating a dielectric resonator 20. Thedielectric resonator 20 and a shield case 35 are mounted on a rotaryjoint 42, to be rotated by a motor 46. Connectors 34 a and 34 b areconnected to an oscillator and a detector by a joint 44 through therotary joint 42 respectively. A sample 48 is arranged in approximationto the upper surfaces of the shield case 35 and the dielectric resonator20.

In this case, transmission energy in each direction in the plane of thesample 48 is measured by rotating the dielectric resonator 20 and theshield case 35, and dielectric orientation of the sample 48 is obtainedfrom the anisotropy thereof.

The sample 48 may be sequentially placed, or may be continuously moving.Online measurement is enabled when the sample 48 is continuously moving.

FIG. 15 schematically shows another embodiment for obtaining anisotropy,which does not rotate a dielectric resonator 20 as well as a sample 48but arranges a plurality of dielectric resonators 20 a, 20 b and 20 c soarranged that the directions of electric field vectors generated fromthe dielectric resonators are different in one plane so that the sample48 moves on these dielectric resonators. Referring to FIG. 15, microwavetransmission energy in directions different by 120° from each other isdetected by three dielectric resonators 20 a, 20 b and 20 c, anddielectric orientation of the sample is obtained.

The embodiment of FIG. 15 rotates neither the dielectric resonator 20nor the sample 48, and hence can quickly obtain the dielectricorientation of the sample. When arranging the dielectric resonators 20a, 20 b and 20 c in a line along the travelling direction (direction ofarrow) of the sample 48 as shown in FIG. 15 and synchronizing the timingof detection of the respective dielectric resonators 20 a, 20 b and 20 cand the moving speed of the sample 48, the same place can be measured.

When arranging the dielectric resonators 20 a, 20 b and 20 c in adirection perpendicular to the travelling direction of the sample 48, itfollows that portions different from each other are measured, while theproblem resulting from the difference of the measured places can besuppressed by arranging the same in approximation to each other.

Also when detecting the reflection energy as the embodiment of FIG. 11,the dielectric resonator can be rotated as shown in FIG. 14 or aplurality of dielectric resonators can be arranged while making thedirections of electric field vectors different as shown in FIG. 15.

It has been recognized that, when employing a square resonator whosesample measuring surface is square or rectangular as the dielectricresonator, linear bar-like rod antennas are superior to loop antennas inuniformity of directions of electric field vectors in a measuredin-sample plane as terminals of a microwave exciter and a detector. Thisis described with reference to FIG. 16 to FIG. 20.

FIG. 16 shows electrolytic distribution and resonance frequencies in thecase of applying rod antennas to a square resonator. Referring to (A), arod antenna 56 a of an exciter is arranged on one side through a squareresonator 54 having a rectangular sample measuring surface and a rodantenna 56 b of a detector is arranged on the opposite side thereof. Thebottom surface of the square resonator 54 is arranged in contact with ashielding material 58 of a conductive material. “a” and “b” show thelengths of the shorter and longer sides of the sample measuring surfaceof the square resonator 54, and l shows the height Table in (B) of FIG.16 shows the respective dimensions a, b and l, electric field vectordiagrams in respective resonance modes in the square resonator 54, andcalculated values and measured values of the resonance frequency. Theunit of the resonance frequency is GHz. In the modes having measuredvalues, the calculated values and the measured values of the resonancefrequency substantially coincide and it indicates that the illustratedresonance modes are proper.

Next, distributions of electric field vectors of loop antennas and rodantennas are comparatively shown in the case of employing such a squareresonator. FIG. 17(A) shows the case of employing loop antennas 60 a and60 b, and FIG. 17(B) shows the case of employing rod antennas 56 a and56 b. It is assumed that directions shown by one-dot chain lines inplanes where samples 48 are arranged are 0 degrees.

FIG. 18 shows results of comparing electric field distribution in thecase of employing loop antennas or rod antennas in a cavity resonatorand dielectric resonators. In the case of the square resonators, it wasassumed that the directions of the one-dot chain lines were 0 degreessas shown in FIG. 17, and long and narrow papers (50 mm by 1.5 mm)impregnated with a wave absorber were placed on the sample measuringsurfaces of the square resonators while changing the angle every 30degrees, for measuring resonance peak levels. In the case of the cavityresonator, the long and narrow paper impregnated with the wave absorberwas arranged in a clearance part where a sample was arranged whilechanging the angle every 30 degrees. While terminals of a microwaveexciter and a detector were rod antennas at that time, the horizontaldirection was assumed to be 0 degrees assuming that the antennas werearranged in a vertical direction.

In the case of the cavity resonator, resonance peaks are obtained onlywhen arranging the long and narrow paper impregnated with the waveabsorber in a direction of 0 degrees and a direction of 180 degrees, asshown in (A). It is understood from this that uniformity of the electricfield vector direction is considerate in the cavity resonator.

(B) shows the case of combining a circular dielectric resonator withloop antennas, and indicates that an electric field vector other than aunidirectional component is also present

(C) shows the case of combining a square dielectric resonator with loopantennas, and indicates that electric fields are directed to respectivedirections in this case and uniformity is inferior.

(D) shows the case of combining a square dielectric resonator with rodantennas, and indicates that it has electric fields having superioruniformity to the case (B) of employing loop antennas although electricfield vectors other than a unidirectional component are also present

FIG. 19 and FIG. 20 show results of measuring a sample with such adielectric resonator. As shown in FIG. 19(A), glass fiber was employedas a sample 48 in a measuring instrument combining a square dielectricresonator 54 with loop antennas 60 a and 60 b and its direction was madeto differ by 90 degrees as shown in (B) and (C) in FIG. 19 for measuringresonance. Consequently, although frequency shifting is observed asshown in FIG. 19(D), the shift quantity is small at approximately 0.6MHz.

On the other hand, in FIG. 20, a square dielectric resonator 54 wascombined with rod antennas 56 a and 56 b as shown in (A), and glassfiber was similarly employed as a sample 48 and measurement was madewhile making the direction different by 90 degrees. Consequently,resonance frequency shifting was large and reached 1.7 MHz as shown inFIG. 20(B), and it indicates that measurement of higher sensitivity canbe made.

FIG. 21 shows an embodiment having a shielding member. As shown in (A),a circular dielectric resonator 62 is stored in a shield case 64 formedby a cylindrical container of brass, the bottom surface of thedielectric resonator 62 is in contact with the shield case 64, and theupper surface of the dielectric resonator 62 and an opening part of theshield case 64 are set flush with each other. A rod antenna 56 a of anexciter and a rod antenna 56 b of a detector are arranged between theside surface of the dielectric resonator 62 and the inner wall surfaceof the shield case 64 in positions opposed through the dielectricresonator 62. A sample 48 is arranged to be close to the upper surfaceof the dielectric resonator 62. A shielding member 66 of brass isarranged above a surface of the sample 48 opposite to the dielectricresonator 62.

While Q at the resonance frequency of this dielectric resonator was 900when arranging no shielding member 66, Q increased to 1700 whenarranging the shielding member 66 on a position separated from theopening end of the shielding case 64 by a distance L of 30 mm.

FIG. 21 (B) shows an electric field vector of the dielectric resonator62 of this embodiment, and the mode is HEM_(11δ+1). The electric fieldincludes a unidirectional component on a sample measuring surface.

FIG. 22 shows a resonance spectrum obtained by measuring a sheet-likesample of 192 μm in thickness of biaxially oriented (bi: axialyoriented) PET (polyethylene terephthalate) with the dielectric resonator(that having the shielding member 66) of this embodiment

FIG. 23 shows variance of the resonance frequency when rotating thesample in a plane as to a peak in the resonance spectrum shown by arrow.FIG. 23 shows, with reference to the resonance frequency in blankmeasurement when placing no sample, frequency variance therefrom withrespect to a rotational angle. The coordinates in the radial directionare set at 6.5 MHz at the center, and at 7.0 MHz on the periphery. Fromthis result, it can be clearly read that the PET sheet comprisesdielectric anisotropy in the plane.

FIG. 24 shows another embodiment measuring dielectric anisotropy of asample while rotating neither a dielectric resonator nor a sample. Threepairs of rod antennas are arranged around a circular dielectricresonator 62. 56 a-1, 56 a-2 and 56 a-3 are rod antennas of an exciter,and 56 b-1, 56 b-2 and 56 b-3 are rod antennas of a detector. The rodantennas 56 a-1 and 56 b-1 are arranged to hold the resonator 62 in apair, 56 a-2 and 56 b-2 are arranged to hold the resonator 62 in a pair,and 56 a-3 and 56 b-3 are arranged to hold the resonator 62 in a pair.Each rod antenna is so arranged that the direction of an electric fieldvector generated by the rod antenna 56 a-1 and the direction of anelectric field vector generated by the rod antenna 56 a-2 form 60degrees, and the direction of an electric field vector generated by therod antenna 56 a-2 and the direction of an electric field vectorgenerated by the rod antenna 56 a-3 further form 60 degrees. 70 is anoscillator of the exciter, and connection between the oscillator 70 andthe rod antennas 56 a-1 to 56 a-3 is successively switched by adistributor 65. 72 is a detector, and connection between the detector 72and the rod antennas 56 b-1 to 56 b-3 is successively switched by adistributor 67. The distributors 65 and 67 are synchronously controlledby a switching driver 68 to make each pair of rod antennas connected tothe oscillator 70 and the detector 72 respectively.

In the embodiment of FIG. 24, resonance spectra of three directionsdifferent by 60 degrees can be measured when a sample is present on asample measuring surface of the resonator 62 by switching operating rodantenna pairs by the switching driver 68, and dielectric anisotropy in asample plane can be measured while rotating neither the sample nor theresonator 62.

While the sample measuring surface of the resonator 62 is circular inthe embodiment of FIG. 24, uniformity of electric field vectors isimproved when the sample measuring surface is rather polygonal thancircular in the case of employing rod antennas as the terminals of theoscillator and the detector. Therefore, the shape of the samplemeasuring surface of the resonator 62 can be rendered orthohexagonal inthe embodiment of FIG. 24.

FIG. 25 schematically shows a computer as a data processor processingmicrowave detection output data converted to a digital signal by an A-Dconverter and captured. 80 is a CPU, 81 is a control part, 82 is a datastorage memory, 83 is a display unit such as a CRT or a liquid crystalpanel, 84 is a printer, and 85 is an input unit such as a keyboard andothers.

In the control part 81, a control program storage part 811 includes amicrowave power supply program and others in addition to a programcontrolling operations of the overall device. A sample control programstorage part 812, for example, stores a program controlling theoperation of rotating the sample or the dielectric resonator in theembodiment of FIG. 14, or the operation of switching the operating rodantenna pairs in the embodiment of FIG. 24. A sampling program storagepart 813 stores a sampling program for detection data, and the samplingprogram controls the timing of detection data sampling and the timing ofA-D conversion by the A-D converter 138. A data processing programstored in a data processing program storage part 814 controls processingsuch as storage, arithmetic processing and others of measurement data(including data such as transmission or reflection microwave intensitydetection data and a measured microwave frequency corresponding thereto,a use number, a rotational angle of a sample and the like) sampled andintroduced into this data processor, and performs formation of anorientation pattern from the measurement data and operation induction ofthe orientation direction and the degree of orientation.

An output program stored in an output program storage part 815 controlsan operation of selecting the orientation pattern, the orientationdirection, the degree of orientation and the like at any time andoutputting the same to the display unit 83 or the printer 84.

The data storage memory 82 comprises an input buffer memory area 821 fortemporarily storing the measurement data introduced into this dataprocessor, a processing data area 822 storing processing datacalculating the orientation direction, the degree of orientation, theorientation pattern and others from these data, a storage area 823 ofbasic data for data processing, an output buffer memory area 824 storingor updating displayed or printed data at any time and the like.

A rotary encoder 53 is provided for detecting the rotational angle of asample or a dielectric resonator. 52 is a frequency counter, which isprovided on, for example, a microwave oscillator. A rotational anglesignal of the sample by the rotary encoder 53 and a measured frequencysignal by the frequency counter 52 are introduced into this dataprocessor in correspondence to sample transmission or reflectionmicrowave intensity detection data by the A-D converter.

What is claimed is:
 1. An orientation measuring instrument comprising: adielectric resonator having a plane being in contact with a sample,sample dielectric resonator arranged on a first surface of the sample; amicrowave exciter generating an electric field vector having aunidirectional component at a frequency in the vicinity of the resonancefrequency of said dielectric resonator when the sample is present and inan in-sample plane parallel to said plane in said dielectric resonator;a detector detecting transmission energy or reflection energy by saiddielectric resonator; a rotation mechanism rotating said sample or saiddielectric resonator in a plane parallel to said plane; and a dataprocessor obtaining dielectric anisotropy of the sample from variance ofa detection output of said detector following rotation by the rotationmechanism whereby said orientation measuring instrument measuresorientation of a portion of the sample.
 2. An orientation measuringinstrument comprising: a plurality of dielectric resonators comprisingplanes being in contact with a sample and arranged close to each other,said dielectric resonators arranged in a first surface of the sample; amicrowave exciter generating electric field vectors havingunidirectional components, being electric filed vectors havingdirections different from each other at a frequency in the vicinity ofthe resonance frequency of said dielectric resonator when the sample ispresent and in an in-sample plane parallel to said planes in therespective dielectric resonators; detectors for the respectivedielectric resonators detecting transmission energy or reflection energyby these dielectric resonators; and a data processor obtainingdielectric anisotropy of the sample from variance of detection outputsby said detectors at said electric field vectors of different directionsfrom said plurality of dielectric resonators whereby said orientationmeasuring instrument measures orientation of a portion of the sample. 3.An orientation measuring instrument comprising: a dielectric resonatorhaving a plane being in contact with a sample, said dielectric resonatorarranged on a first surface of the sample; a plurality of sets, beingsets of microwave exciters generating electric filed vectors havingunidirectional components at a frequency in the vicinity of theresonance frequency of said dielectric resonator when the sample ifpresent and in an in- sample plane parallel to said plane in saiddielectric resonator and detectors detecting transmission energy orreflection energy by said dielectric resonator, arranged on positionsdifferent from each other with respect to said dielectric resonator; aswitching driver selecting one set among said plurality of sets ofmicrowave exciters and detectors and sequentially driving the same; anda data processor obtaining dielectric anisotropy of the sample fromvariance of detection outputs of said detectors following switching bysaid switching driver whereby said orientation measuring instrumentmeasures orientation of a portion of the sample.
 4. The orientationmeasuring instrument in accordance with any of claims 1 to 3, employingvariance of the resonance frequency as variance of said detectionoutput(s).
 5. The orientation measuring instrument in accordance withclaim 1, 2 or 3, employing variance of detection energy at a specificfrequency as variance of said detection output(s).
 6. The orientationmeasuring instrument in accordance with claim 1, 2 or 3, wherein saidexciter(s) and said detector(s) comprise a terminal pair oppositelyarranged through the dielectric resonator(s) for detecting transmissionenergy by said detector(s).
 7. The orientation measuring instrument inaccordance with claim 1, 2 or 3, wherein said exciter(s) and saiddetector(s) comprise a common terminal arranged closely to thedielectric resonator(s) for detecting reflection energy by saiddetector(s).
 8. The orientation measuring instrument in accordance withclaim 1, 2 or 3, wherein said dielectric resonator(s) is a cylindricalresonator.
 9. The orientation measuring instrument in accordance withclaim 1, 2 or 3, wherein said dielectric resonator(s) is a squareresonator.
 10. The orientation measuring instrument in accordance withclaim 1, 2 or 3, wherein terminals of said exciter(s) and saiddetector(s) are bar-like rod antennas having been arranged in adirection perpendicular to the plane(s) of said dielectric resonator(s)being close to or being in contact with the sample.
 11. The orientationmeasuring instrument in accordance with claim 1, 2 or 3, wherein theperiphery of said dielectric resonator(s) is covered with a shieldingmaterial consisting of a conductive material except a sample measuringsurface.
 12. The orientation measuring instrument in accordance withclaim 11, wherein a shielding material consisting of a conductivematerial is arranged also on a sample measuring surface side of saiddielectric resonator(s), and the sample is arranged between the samplemeasuring surface of the dielectric resonator(s) and said shieldingmaterial on the sample measuring surface side.